Pairing from repulsion in a two-dimensional Fermi gas with soft-core interactions
Abstract: We investigate a model many-body system of spinless Fermi gas in two dimensions, where the bare two-body interaction is repulsive and takes the form of a soft-core disk potential. We obtain the zero temperature phase diagram of this model by numerical functional renormalization group (FRG), which retains the effective interaction vertices in all channels to provide a detailed picture of how Cooper pairing emerges under the renormalization flow. The repulsion drives the system to a series of superfluid states with higher angular momentum paring, for example in the $f$- and $h$-wave channels instead of the $p$-wave channel. This is in sharp contrast to the original Kohn-Luttinger mechanism where pairing of very large angular momenta and exponentially small transition temperature was predicted. We trace the stabilization and enhancement of $f$- and $h$-wave pairing back to the momentum dependence of the bare interaction. A perturbative calculation is carried out to show that while the second order Kohn-Luttinger diagrams provide a qualitative understanding of the onsets of the various superfluid phases, they are unable to accurately capture the phase boundaries predicted by FRG. Our findings suggest that tuning the shape of the interaction potential offers a promising route to achieve stronger ``pairing glue" and to realize nontrivial superfluid phases in repulsive Fermi gases beyond the scope of the original Kohn-Luttinger analysis.
- P. W. Anderson, Is there glue in cuprate superconductors?, Science 316, 1705 (2007).
- P. Monthoux, D. Pines, and G. Lonzarich, Superconductivity without phonons, Nature 450, 1177 (2007).
- P.-G. De Gennes, Superconductivity of metals and alloys (CRC press, 2018).
- S. Maiti and A. V. Chubukov, Superconductivity from repulsive interaction, in AIP Conference Proceedings, Vol. 1550 (American Institute of Physics, 2013) pp. 3–73.
- M. Y. Kagan, V. A. Mitskan, and M. M. Korovushkin, Anomalous superconductivity and superfluidity in repulsive fermion systems, Physics-Uspekhi 58, 733 (2015).
- R. Shankar, Renormalization-group approach to interacting fermions, Rev. Mod. Phys. 66, 129 (1994a).
- W. Kohn and J. M. Luttinger, New Mechanism for Superconductivity, Phys. Rev. Lett. 15, 524 (1965).
- J. M. Luttinger, New mechanism for superconductivity, Phys. Rev. 150, 202 (1966).
- D. Fay and A. Layzer, Superfluidity of low-density fermion systems, Phys. Rev. Lett. 20, 187 (1968).
- M. Y. Kagan and A. Chubukov, Possibility of a superfluid transition in a slightly nonideal fermi gas with repulsion, JETP Lett 47, 614 (1988).
- A. V. Chubukov, Kohn-Luttinger effect and the instability of a two-dimensional repulsive Fermi liquid at T=0, Phys. Rev. B 48, 1097 (1993).
- A. Keleş, E. Zhao, and X. Li, f𝑓fitalic_f-wave superfluidity from repulsive interaction in rydberg-dressed fermi gas, Phys. Rev. A 101, 023624 (2020).
- P. Kopietz, L. Bartosch, and F. Schutz, Introduction to the Functional Renormalization Group (Lecture Notes in Physics) (Springer, 2010).
- A. Keleş and E. Zhao, Competing many-body instabilities in two-dimensional dipolar fermi gases, Phys. Rev. A 94, 033616 (2016).
- R. Shankar, Renormalization-group approach to interacting fermions, Rev. Mod. Phys. 66, 129 (1994b).
- M. Baranov, A. Chubukov, and M. Yu. Kagan, Superconductivity and superfluidity in fermi systems with repulsive interactions, International Journal of Modern Physics B 6, 2471 (1992).
- X. Li and S. D. Sarma, Exotic topological density waves in cold atomic Rydberg-dressed fermions, Nat. Commun. 6, 7137 (2015).
- J. A. Sauls, f𝑓fitalic_f-wave correlations in superfluid He3superscriptHe3{}^{3}\mathrm{He}start_FLOATSUPERSCRIPT 3 end_FLOATSUPERSCRIPT roman_He, Phys. Rev. B 34, 4861 (1986).
- W.-C. Lee, C. Wu, and S. Das Sarma, f𝑓fitalic_f-wave pairing of cold atoms in optical lattices, Phys. Rev. A 82, 053611 (2010).
- B. Xiong, H. H. Jen, and D.-W. Wang, Topological superfluid by blockade effects in a rydberg-dressed fermi gas, Phys. Rev. A 90, 013631 (2014).
- A. S. Alexandrov and V. V. Kabanov, Unconventional high-temperature superconductivity from repulsive interactions: Theoretical constraints, Phys. Rev. Lett. 106, 136403 (2011).
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